Shutdown notification scheduler in PreDestroy

application/src/main/java/org/thingsboard/server/service/notification/DefaultNotificationSchedulerService.java

@@ -41,6 +41,7 @@ import org.thingsboard.server.service.executors.NotificationExecutorService;
 import org.thingsboard.server.service.partition.AbstractPartitionBasedService;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -66,6 +67,7 @@ public class DefaultNotificationSchedulerService extends AbstractPartitionBasedS
 
     private final Map<NotificationRequestId, ScheduledRequestMetadata> scheduledNotificationRequests = new ConcurrentHashMap<>();
 
+    @Override
     @PostConstruct
     public void init() {
         super.init();
@@ -167,6 +169,13 @@ public class DefaultNotificationSchedulerService extends AbstractPartitionBasedS
         return "notifications-scheduler";
     }
 
+    @Override
+    @PreDestroy
+    public void stop() {
+        super.stop();
+        scheduler.shutdownNow();
+    }
+
     @Data
     private static class ScheduledRequestMetadata {
         private final TenantId tenantId;